This invention concerns mattress pads or overlays in general, and in particular a mattress pad having a variety of features for providing sectioned support areas collectively functioning as a coordinated system for improved pressure dispersion for all parts of a user's body.
Decubitus ulcers, also known as bed sores, are a significant concern for bed-ridden patients. The problem of prolonged pressure on natural bony projections of a patient (such as the scapula, sacrum, and trochanter) is compounded in acute care settings where the patient cannot be frequently turned or moved. It is relatively common practice in hospitals in the United States for a flexible polyurethane foam mattress overlay to be used to supplement the mattresses of acute care patients. The goal generally is to provide at least some relief from bed sores during their immobilization. Simple convoluted foam pads, readily produced with known machinery, are typical of mattress overlays in present use.
A major thrust in recent hospital care practices has included higher-developed cost consciousness. To reduce costs, a trend has developed whereby convoluted foam pads are provided with relative taller conical peaks and thinner bases so that the pad may be produced with less foam (and hence be more cheaply provided). Many of such convoluted foam pads typically provide uniform instead of differentiated support across their entire patient support surface. Accordingly, effective pressure distribution for the prevention of decubitus ulcers is not optimized for all parts of a patient's body.
Other forms of cushions or pads are known. For example, Derman (U.S. Pat. No. 2,638,156) discloses a seat-type cushion having a substantially flat support surface, but utilizing density variations for different segments thereof to variably support the ischial tuberosites of a user's pelvis. Variations in density may be obtained in alternative ways, but particularly include the production of channels and cavities through the cushion (i.e., the removal of material). Rogers (U.S. Pat. No. 3,885,257) also varies support provided with a defined section of a pad by varying the amount of material removed from around projections formed thereby. However, the cross-sectional area of the external support surface of each projection is maintained constant over an entire block of his invention. Furthermore, the generally to substantially reduced cross-sectional area of such projections beneath the upward external support surface thereof can cause such projections to buckle, twist, and/or become unusually compressed, during load bearing, with possible unintended modification of the support action offered thereby.
Thompson (U.S. Pat. No. 4,110,881) discloses a process for fabricating a mattress including the making of slots of varying depth and/or spacing therein so as to alter the support provided thereby. Removal of material is not ordinarily significant nor a design parameter. Instead, slicing is effected to provide a foamed material mattress which mimics the function of "inner spring" mattresses.
In addition to such cutting (i.e. slicing) and coring (i.e. producing cavities) other processing of foam products may be effected. For example, Spann (U.S. Pat. No. 4,573,456) discloses air channels which may be formed in a foam block for dissipating heat and moisture away from a person utilizing a product made from such foam block. And, though not in all circumstances analogous to foam pads, other types of mattress supplements are generally known. For example, Douglas (U.S. Pat. No. 4,279,044) discloses a fluid support system with automatic valving for distributing the body weight of a patient received thereon.